Estimation of Thermodynamic and Transport Properties of Metallic Materials

A three-layer apparatus for thermal property measurements (conductivity and capacity) of high-conductivity specimens where an electrical heater is sandwiched between two samples having same thickness and material is investigated. In particular, the heater is so thin that can be modelled as a lumped body along the heat diffusion direction and, hence, by using a boundary condition (BC) of the fourth or sixth kind at the heated surface of the specimen. Specifically, a BC of the 4th kind or Carslaw type accounts for the heater heat capacity, while the one of the 6th kind considers also the imperfect contact between heater and sample. Once the transient temperature distribution within the slab-shaped sample is known and the related sensitivities are evaluated, an optimal experiment is designed by applying the D-optimum criterion to estimate accurately and simultaneously conductivity (k) and capacity (C). Then, the standard deviations of the estimates are also computed.